In related art, an image sensor performs CDS (Correlated Double Sampling) processing in which A/D (Analog-to-Digital) conversion is performed on reset components and signal components in each vertical column of pixels, and each of differences between the rest components and the signal components is determined to reduce noise.
In the CDS processing, for example, a count value of the reset component is down-counted and held, and after that, a count value of the signal component is up-counted from the held count value to determine a difference between the reset component and the signal component.
On the other hand, an image sensor storing a count value in a storage element with use of a Gray code or a phase shift code as a clock signal has been proposed (for example, refer to PTL 1).